Spud growers have bounced back with a bumper – and colourful – crop ready for
crisping, says Maria Fitzpatrick.

I feel like I’m on a field trip from the Willy Wonka school of agriculture. I’m standing in a field in Ross-on-Wye, Herefordshire, watching two grown men excitedly dig up potatoes and cut them in half to reveal the results of their latest experiment. The potatoes are marbled red or deep blue inside and it’s quite surreal to see.

These miracle potatoes come from a collaboration – but also a challenge – between Tyrrells, the Herefordshire crisp company, and farmer Henry Chinn of Cobrey Farms. “Yes, they’ll do nicely,” he says, grinning widely. When they’re fully grown, the 'Burgundy Red’, 'Bergerac’ and 'Salad Blue’ varieties will join their pale cousin, the 'Lady Rosetta’, in a jumbled bag of patriotic crisps.

Cobrey Farms, a prominent grower in Herefordshire since the Twenties, is one of the main growers for Tyrrells, which was founded by William Chase, a potato farmer, in 2002. William started making small batches of hand-cut crisps in the old potato sheds in Tyrrells Court Farm in Leominster, and trialling them at local farm shops at a time when provenance was firmly back on the agenda. Today, such is the demand for English-grown potato crisps (even in France, a fact they’re proud of) that nine other family-run farms in the region, including Henry’s, all part of a growing cooperative, supply them.

Henry’s mood this morning is as much about relief as it is jollity. “After the year we had last year, things feel so much more positive,” he says. The farming community was facing a real nightmare because of heavy rainfall: the reality of throwing crops away. Crisis calls to the Farming Community Network helpline doubled. “We had the worst year of rain that this area has experienced for a century,” Henry says. “Usually we’d get 26in a year – last year it was 54in, and most of that fell between June and September, our peak harvest time.”

Potatoes only have about 24 hours under water before they rot, so the harvest became a race against time for farmers like Henry. A 25 per cent yield reduction was common across the county. Farmers start to plant in September and October for the following year, so every aspect of their operation was affected.

Another local potato farmer, Frank Green, had to resort to desperate measures. A quarter of his crop was still in the ground in November, explains Patrick Lewis, from Gamber, the agricultural produce company that coordinates the growing operation and logistics for Tyrrells. “He had to find £380,000, the price of a house, for a self-propelling harvester that could lift potatoes out of the waterlogged soil. If it had been left a week longer the whole crop would have been lost.”

Farmer Henry Chinn in the potato fields (ANDREW CROWLEY)

Add to that the fact that the fields need at least a five-year rotation and it’s no wonder that our potato farmers have had to diversify; historically in Herefordshire it was all about potatoes, but many farms (3,000-acre Cobrey Farms included) now grow asparagus, rhubarb, blackberries and vines.

“Their resilience is amazing,” says Patrick. “With the weather of the last few years, potatoes have been a gamble, and there are no subsidies.” However, the crisp market has boomed during the recession, so year-round demand is growing. “These guys just crack on when conditions are favourable.”

And thank goodness, now they are. Everything is three weeks late, a knock-on effect of last year, but the crop is healthy and plentiful. I climb on the harvester to witness hundreds of 'Lady Rosetta’ potatoes, with their cricket-ball shape and strong potato flavour, whizzing into the hopper. It’s an efficient but delicate process, explains Rob, who’s manning the machine. “We have eight cameras to show us what’s happening as they’re dug up and loaded,” he tells me, pointing around the cabin. “We have to make sure they don’t bruise from being jostled or falling too hard.”

Red and blue potato varieties (ANDREW CROWLEY)

This end of the county, with its sandy red soil, is perfect for growing “early” potatoes – that is, genuinely “new” potatoes that the Potato Council has been highlighting this year while encouraging us to “celebrate the British season”. Real new potatoes are not just small potatoes, they are a seasonal crop harvested between May and October and on the shelf within days. With their easily scraped skins, they don’t last in store – unlike potatoes grown at Tyrrells Court Farm, where the clay soil is heavier – and so are taken straight from the field and turned into crisps, with their jackets still on. They “lift” potatoes as close as possible to when the crisps are needed to capture their freshness, so local means everything. Tyrrells’s all-time record of lifting, processing and delivering crisps to Ludlow Food Centre farm shop took 43 minutes. This year, even seeds that were once sourced in Scotland or Yorkshire came from within 40 miles.

The 'Lady Rosettas’ we’re digging up today, a perfect “chipping” variety, are some of the best Henry has seen for two years, with the desired 12-20 potatoes per root. The year before last, there were drought problems; the ideal growing temperature is 18-23C, and in 2011 it reached 28C, shocking the potatoes so they stopped growing, then started off inferior secondary growths when the temperature cooled. When it comes to crisps, everything from size (they need to fit in the packet) to the starch content – which can affect the colour when they are fried – matters, so varieties are chosen with great care.

Once the potatoes have been graded, clods removed, and washed, it’s time for the fun. At Tyrrells Court Farm, sliced potatoes are “swooped” through cooking oil, whizzed about tumble-drier style to shake it off, then danced up and down in chutes, being dressed with their seasoning, before they are inspected for the perfect curl, crunch and flavour. As for those red, white and blues, the grower has done the groundwork; they emerge like potpourri, almost too good to eat… almost.

The crisping process is simple, and the act of crunching into them so casual it belies the pains that are taken where their journey begins. As Patrick Lewis reflects, “Without the dedication and passion of the local growers, quite simply we are nothing.”

Tyrells's homemade crisps recipe

Choose a nice, firm, waxy potato such as Charlotte and slice using a mandolin. We like to keep the peel on our potatoes, you might like to do the same for extra authenticity and character.

Soak the slices in cold water for an hour or so then drain and dry carefully but thoroughly.

Heat sunflower oil to 340F/170C in a small domestic fryer or a sturdy high sided pan (the oil needs to be about 1in deep) and drop in the potato slices a few at a time.

If the oil has reached the right temperature, then the potato slices should sizzle gently as soon as they’re dropped. They should need no more than six minutes in the oil (try to turn them half way through) and drain out once they’re a lovely golden colour and crisp.

Drain on kitchen towel, transfer to a bowl then sprinkle with your favourite ingredients while the crisps are warm. We love Maldon sea salt flakes, or a blend of sea salt and crushed black peppercorns.

You could also try Parmesan shavings, jalapeño chilli flakes or a sprinkle of paprika.

The Telegraph, in association with Love British Food, is running a competition to find the most inclusive and innovative harvest celebration to take place during British Food Fortnight (now until October 6). Enter your celebration before October 10.